Molecular characterization of a complex translocation in a newborn infant

A newborn infant was referred because of low-set ears, mild downward slant of the palpebral fissues, micrognathia with higharched palate, a flat midface, small mouth, and thin upper lip with cupid bow configuration. To some extent her cry resembled that associated with cri du chat syndrome. Cytogenetic findings with G- and Q-banding alone failed to characterize precisely the complex translocations. By the chromosome in situ suppression (CISS) hybridization technique using whole chromosome specific probes, a complex 4 breakpoint rearrangement involving both arms of a single chromosome 1 with the long arms of chromosome 5 and 11 was disclosed, i.e., 46,XX, der(1),t(1;5) t(1;11) (5qter→5q31::1p31.3→1q44::11q23→11qter;5pter→5q31::1p31.3→1pter;11pter→11q23::1q44→1qter). Gene deregulation and position effect may explain the multiple anomalies in individuals with apparently balanced translocations may shed some light towards unveiling the clinical consequences associated with aberrations which are presumably balanced. © 1993 Wiley-Liss, Inc.     

The role of hemagglutinins in the midgut extracts of two lines of Aedes aegypti in their susceptibility to Dengue-2 virus

Hemagglutinin activity (HA) was studied in the midgut extracts from highly (h) and lowly susceptible strains of Aedes aegypti mosquitoes to Dengue-2 virus (DEN-2). HA in the midgut extracts from these two isofemale strains of mosquitoes was high in as compared to (h) mosquitoes. HA was found to be higher with chicken red blood cells (RBCs) than with rabbit and human RBCs of O group. Larval midgut extracts showed higher activity than those from adult female mosquitoes. Exposure of midgut extracts to 100 degrees C for 10 mins destroyed the activity. The activity was observed between pH 6 and pH 10. HA in midgut extracts was also studied using twenty different carbohydrates; five of them showed an inhibition of HA. The inhibitory carbohydrates, when incorporated into DEN-2-infected bloodmeal, showed a reduction in the susceptibility of mosquitoes to the virus as compared to the control ones fed on the virus alone. Similarly, when these carbohydrates were incorporated in the DEN-2-infected inoculum, the inoculated mosquitoes showed a reduction in the susceptibility to the virus. HA in the virus-infected midgut extracts was higher than that in the uninfected controls. These results suggest that the presence of HA in the midgut may be one of the factors that affect the susceptibility of Ae. aegypti mosquitoes to DEN-2.     

Ring chromosome 8 syndrome: further characterization

We describe two de novo cases of extra r(8) confirmed by fluorescent in situ hybridization (FISH). Based on these two and eight additional cases of extra r(8) confirmed by FISH, the phenotype is better documented. One of our patients had minor facial anomalies, near-normal growth, and neurological development. She had a ring in each cell analyzed. The second had minor craniofacial anomalies and growth and mental retardation. He had a small or double-sized ring in each cell. The phenotype of these 10 cases ranges from almost normal in an adult with 10% mosaicism to variable degrees of minor anomalies, growth retardation, and mental retardation overlapping the mosaic +8 syndrome.     

Distinct types of T-cell help for the induction of a humoral immune response to Streptococcus pneumoniae

Studies have indicated that purified soluble polysaccharide antigens can elicit T cell-independent Ig responses in vivo, although these responses can be modulated by T cells in a noncognate manner. Relatively little is known, however, concerning the parameters that regulate polysaccharide-specific, as well as protein-specific, Ig isotype responses to an intact extracellular bacterium. Using the murine in vivo humoral response to intact Streptococcus pneumoniae as a model it can be shown that CD4+ T-cell receptor alphabeta+ T cells deliver help for both polysaccharide- and protein-specific Ig responses. However, these responses differ fundamentally in their mechanism of action.     

Ultrastructural comparison between regenerating and developing hindlimbs of Xenopus laevis tadpoles

Hindlimbs of Xenopus laevis tadpoles at stages 50 to 55 of embryonic development were amputated in order to study the fine structure associated with ontogenetic decline in regenerative ability of this anuran. Regenerating hindlimbs were compared with their contralateral developing limb so as to determine the similarities and differences in ectodermal-mesenchymal ultrastructural relationships in these systems. Prior to stage 53, mesenchymal cells in regenerating limbs, as well as mesenchyme cells in developing limbs appear undifferentiated; the cells are not visibly different. However, at stage 54 muscle and cartilage differentiation in the developing foot is distinct. Furthermore, in all larvae with regenerates at stages 50 to 52 the basal lamina is not evident subjacent to the apical tip of the epithelium which covers the amputation surface. A distinct basal lamina is present, however, beneath the epidermis in all embryonic limbs examined, including the apical tip, as well as in regenerates of stages 53 to 55 tadpoles. Also, a greater apical accumulation of extracellular matrix (ECM) and organized collagen is observed among the mesenchymal cells in regenerates of stages 53 to 55 tadpoles, and among the mesenchyme cells in developing limbs of stages 50 to 55, compared with pre-stage 53 regenerates. In cases in which an embryonic limb bud is composed of relatively undifferentiated cells (stages 50 to 52), events following amputation result in the complete regeneration of a limb. However, when amputated embryonic limbs contain differentiating tissues, (e.g., muscle and cartilage) only selective tissues undergo regeneration resulting in malformed (heteromorphic) regenerates.(ABSTRACT TRUNCATED AT 250 WORDS)     

A unique, complex variant philadelphia chromosome translocation in a patient with typical chronic myelogenous leukemia

The Philadelphia (Ph) chromosome [der(22) t(9;22)(q34;q11)] is the characteristic chromosomal abnormality found in chronic myelogenous leukemia (CML). This chromosome has been reported in patients with other chromosomal abnormalities. In this study, we describe a patient with hematologically typical chronic-phase CML with an unusual and complex translocation involving chromosomes 9, 11, and 22. These complex translocations were identified by G-banded conventional cytogenetics and confirmed by fluorescence in situ hybridization (FISH) using whole chromosome painting probes (wcp). To the best of our knowledge, these are unique translocations involving the short and the long arms of chromosome 9 in 4 different translocations with the short arm of chromosome 11 and the long arm of chromosome 22.     

Reconstitution of T-cell repertoire after autologous stem cell transplantation: influence of CD34 selection and cytomegalovirus infection.

The period of immunodeficiency following autologous hematopoietic stem cell transplantation is characterized by transient expansions of CD8+CD45RO+CD57+ T lymphocytes, displaying markers of an activated phenotype. Most evidence suggests that this early reconstitution results from proliferation of mature T cells that have survived conditioning or were transferred with the graft. Although homeostatic mechanisms are thought to act in maintaining total T-cell numbers, the degree to which antigen-driven expansions contribute and the nature of the stimulating antigens remain unclear. CD34 selection of stem cell grafts reduces the available T-cell pool, potentially delaying immune reconstitution and resulting in increased infective complications. In the allogeneic transplantation setting, lymphopenia has been associated with cytomegalovirus (CMV) infection risk and, if persistent, with adverse outcome. We prospectively studied patients undergoing CD34-selected (n = 13) or unselected (n = 13) autologous hematopoeitic stem cell transplantation for immune reconstitution and CMV infection. No significant differences were demonstrated between graft types with respect to lymphocyte subset recovery, T-cell receptor beta-chain variable region spectratype diversity, or CMV DNA detection rates (45% versus 40%). CMV infection was associated with a trend toward higher rather than lower CD8+ counts at 6 weeks posttransplantation (P =.08) that became significant by 3 months (P=.007), and that was associated with decreased T-cell receptor beta-chain variable region spectratype diversity (P =.01). CMV-specific HLA-tetramer analysis demonstrated transient expansions with CDR3 lengths corresponding to those of some of the major posttransplantation T-cell expansions demonstrated by spectratype analysis suggesting that CMV-specific T cells contribute to the pattern of immune reconstitution.     

Prophylactic mastectomy: pathologic findings in high-risk patients

BACKGROUND: According to recently published data, prophylactic mastectomy (PM) appears to prevent about 90% of the expected malignant neoplasms in women with a family history of breast cancer. OBJECTIVES: To identify the frequency of high-risk lesions in PM specimens and to determine occurrence of any new primary breast cancer following PM. DESIGN: We performed a retrospective study of women undergoing unilateral or bilateral PM. Medical charts and pathologic findings of 35 patients who underwent bilateral mastectomies at University Hospital, Syracuse, NY, from 1989 to 1996 were reviewed. Patients with biopsy-proven bilateral breast cancer were excluded. Patients were divided into 3 groups: (A) positive family history and no known breast cancer (n = 9), (B) positive family history and contralateral neoplasia (n = 13), and (C) negative family history and contralateral neoplasia (n = 13). These findings were compared with those found in reduction mammoplasty specimens from 10 women at standard risk of breast cancer. RESULTS: The mean age of the control group of women undergoing reduction mammoplasty was 38 years. The pathologic specimens demonstrated no significant pathologic findings in 9 and fibrocystic change in 1. In group A, the mean number of affected relatives was 3.1, and the mean age was 38 years. Two of these 9 women had atypical duct hyperplasia and 1 had atypical lobular hyperplasia in their breasts (ie, 33% with high-risk pathologic findings). Of the 13 group B women (mean age, 46.6 years; mean of 2.5 affected relatives and unilateral breast cancer), the contralateral PM specimen contained duct carcinoma in situ in one and invasive ductal cancer in a second (15% with occult malignant neoplasms). In 13 group C patients (mean age, 47.1 years), 3 (23.1%) of the contralateral PM specimens displayed atypical duct hyperplasia or atypical lobular hyperplasia. At a mean follow-up of 4.8 years, there have been no new breast malignant neoplasms in these 45 women. CONCLUSIONS: The occurrence of unilateral cancer in patients with family history of breast cancer is associated with a 15.4% probability of simultaneous occult malignant neoplasms in the contralateral breast. Patients with a strong family history but no evidence of breast cancer have a substantially similar rate of proliferative disease in their PM specimens as those women who have unilateral cancer but no significant family history.